Ophthalmic range finding

ABSTRACT

Systems and methods for analyzing the anatomy of a patient&#39;s eye with circular or rotated polarized laser beams, or with laser beams of different wavelengths are disclosed. One system includes a polarization beam-splitter and a quarter-wave plate, wherein the quarter-wave plate is configured to circularly rotate a laser beam received from a laser that is transmitted and passes through the polarization beam-splitter, and to transform a circularly rotated back-reflected beam to a linearly polarized laser beam that is perpendicular to the beam that was transmitted through the polarization beam-splitter. Substantially all of the back-reflected beam is directed to a photo-detector for analysis. A Faraday rotator subsystem may be substituted for a polarization beam-splitter. An optical system including a laser that generates a laser beam of a first wavelength for therapeutic treatment, and another laser that generates a laser beam of a second wavelength for measurement is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/531,411 filed Jun. 22, 2012, entitled “OPHTHALMIC RANGEFINDING,” which claims priority to Provisional U.S. Patent ApplicationSer. No. 61/637,644 filed Apr. 24, 2012, entitled “OPHTHALMIC RANGEFINDING,” and Provisional U.S. Patent Application No. 61/500,596 filedJun. 23, 2011, entitled “OPHTHALMIC RANGE FINDING.” The entiredisclosures of the aforementioned applications are hereby incorporatedby reference, for all purposes, as if fully set forth herein.

BACKGROUND

Non-ultraviolet ultra-short pulsed lasers with pulse durations measuredin the femtoseconds and picoseconds range are commonly used to formincisions within corneal tissue to form a LASIK flap. Other ophthalmictreatments involve procedures performed on anatomical features withinthe eye, such as the capsular bag and lens. Such treatments may involvethe removal of cataracts. To ascertain the location and orientation ofthe anatomical features within the eye (e.g., the capsular bag, lens,and the like), either prior to or during surgery, an optical coherencetomography (OCT) system may be used. Such systems, however, aregenerally expensive, limiting their potential acceptance.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention encompass methods and systems foranalyzing the ophthalmic anatomy of a patient posterior to the corneaand/or for providing therapeutic treatment to the ophthalmic anatomy.According to one embodiment, a system for treating an eye of a patientis provided. The eye may include a fluid posterior to a cornea and thesystem may include a femtosecond laser, an optical system, a sensor, anda computing device. The femtosecond laser may be configured fordirecting femtosecond energy along a path and the optical system may bedisposed along the path from the laser. The optical system may include afocusing lens and a scanner so as to scan a non-plasma-generating focusof the femtosecond energy along a path within the patient's eye. Thepath may extend posterior to the patient's cornea within the fluid sothat the path includes a first location disposed within a tissue of theeye and a second location disposed within the cornea. The sensor may beoriented along the path so as to sense a first signal associated with afirst focus location within the eye and a second signal associated witha second focus location within the eye. The computing device may becommunicatively coupled with the sensor and may determine a location ofan interface between the fluid and a tissue of the eye in response tothe first signal and the second signal.

In some embodiments, the sensor may be configured for sensing thesignals in response to the energy generating a plasma at the focus whenthe plasma is disposed in the fluid and when the focus is at the secondlocation. The sensor may include an image acquisition device configuredfor acquiring tissue interface reflectance images and the computingdevice may be configured to determine the location of the fluid/tissueinterface based on a comparison between the first reflectance image andthe second reflectance image. In some embodiments, the sensor may beconfigured to sense a dimension of a spot size at the focus and thecomputing device may be configured to determine if the beam spot size isindicative of wrinkling associated with engagement between the corneaand a corneal-shaping patient interface of the system.

In one embodiment, the computing device is configured to receive OCT orother pre-operative diagnostic data regarding the interface location.Alternatively or additionally, the computing device may be configured todetermine and transmit pachymetry data for the eye. Alternatively oradditionally, the computing device may be configured to determine aseparation between a posterior capsule and a retina of the eye.Alternatively or additionally, the computing device may be configured todetermine a curvature of a patient interface contact surface of thesystem. Alternatively or additionally, the computing device may beconfigured to detect bubbles at a meniscus between a patient interfacecontact surface of the system and the eye. Alternatively oradditionally, the computing device may be configured to determine alocation of an apex or vertex of a contact surface of a patientinterface of the system. In one embodiment, the non-plasma-generatingfocus of the femtosecond energy may have an energy level less than abubble formation threshold of the fluid or the tissue of the eye.

According to another embodiment, a machine-readable medium havingmachine-executable instructions configured to perform a method foranalyzing the ophthalmic anatomy of a patient posterior to the cornea isprovided. The method may include scanning a focus of a femtosecond laserbeam along a path within the patient's eye. At least a portion of thepath may be disposed posterior to the patient's cornea and the path mayinclude a first location and a second location. The method may alsoinclude acquiring a first reflectance image associated with the focusdisposed at the first location and acquiring a second reflectance imageassociated with the focus disposed at the second location. The methodmay further include determining the presence or absence of an ophthalmicanatomical feature of the eye based on a comparison between the firstreflectance image and the second reflectance image.

In some embodiments, the first and/or second reflectance images may beacquired with a CCD camera. The anatomical feature may include acapsular bag, a lens, and/or other anatomical features. In someembodiments, a therapeutic energy may be maintained for the femtosecondlaser beam during the scanning process to provide therapeutic treatmentduring the scanning process. The femtosecond laser beam (tissueidentifying light) signals may be generated in response to differencesin plasma formation when the focal point of the femtosecond laser iseither scanned in the liquid vitreous between tissues of the eye and/orscanned within the tissues of the capsular bag, lens, or endotheliallayers along the posterior of the cornea.

In some embodiments, the method may additionally include operating alaser to provide therapeutic treatment to one or more anatomicalfeatures. Providing a therapeutic treatment may include disrupting acapsular bag, a lens, or another anatomical feature. In one embodiment,the therapeutic treatment includes lens fragmentation, capsulorhexis, orcapsulotomy. In one embodiment, the laser may be the femtosecond laseroperated to scan the patient's eye, in which the femtosecond laser isoperated at a higher energy level to provide the therapeutic treatment.

According to another embodiment, a system for analyzing the ophthalmicanatomy of an eye posterior to a cornea is provided. The system mayinclude a femtosecond laser, an acquiring device, and a computingdevice. A plasma-generating focus of the femtosecond laser beam may bescanned along a path within the eye such that at least a portion of thepath is disposed posterior to the cornea and the path includes a firstlocation and a second location. The acquiring device may acquire a firstreflectance image associated with the focus disposed at the firstlocation and may acquire a second reflectance image associated with thefocus disposed at the second location. The computing device may becommunicatively coupled with the acquiring device so that the computingdevice may determine the presence or absence of an ophthalmic anatomicalfeature of the eye based on a comparison between the first reflectanceimage and the second reflectance image.

In some embodiment, the acquiring device may be configured for sensingthe images in response to the plasma-generated at the focus when thefocus is disposed in the first location and when the focus is at thesecond location.

Embodiments of the present invention also provide an optical system fordetecting back-reflected, circular or rotated polarized laser beams. Inone embodiment, the optical system incorporates a combination of apolarization beam-splitter and a quarter-wave plate to generatecircularly rotated, polarized laser beams. When the laser beam isreflected back from the subject tissue, the direction of the circularrotation is reversed, and when the beam is transformed to a linearlypolarized laser beam, the back-reflected laser beam is not transmittedthrough the polarization beam-splitter, but is instead, deflected to aphoto-detector. Substantially all of the back-reflected laser beam isdetected by the photo detector using this optical system. In anotherembodiment, instead of using a polarization-beam splitter and aquarter-wave plate, the optical system incorporates a Faraday rotatorsubsystem to rotate the polarity of the laser beam and to ultimatelydeflect substantially all of the back-reflected laser beam to aphoto-detector.

Another embodiment provides an optical system that implements at leasttwo laser beams, each of a different wavelength, where one is configuredto perform a therapeutic procedure while the other is configured tomeasure an anatomical feature of a patient's eye. Hence, the opticalsystem incorporates two lasers with one laser generating a laser beamconfigured for therapeutic purposes and the other laser generating alaser beam configured for measuring an anatomical feature of the eye.The wavelength of the laser beam generated by the first laser is longerthan that of the laser beam generated by the second laser.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a laser ablation system according to an embodiment ofthe present invention.

FIG. 2 illustrates a simplified computer system according to anembodiment of the present invention.

FIG. 3 illustrates a wavefront measurement system according to anembodiment of the present invention.

FIG. 3A illustrates another wavefront measurement system according to anembodiment of the present invention.

FIG. 4 illustrates an optical system for performing diagnostic and/ortherapeutic scans according to one embodiment of the present invention.

FIGS. 5A and B illustrate a diagnostic scan that may be performed todetermine the location, depth, and orientation of an anatomical featureof the eye according to one embodiment of the present invention.

FIGS. 6A and B illustrate an optical system for performing diagnosticand/or therapeutic scans according to one embodiment of the presentinvention.

FIG. 7 illustrates incisions of the cornea that may be made by theoptical systems described herein according to one embodiment of thepresent invention.

FIG. 8 illustrates various applanation lenses that may be used accordingto embodiments of the present invention.

FIG. 9 illustrates a method for providing capsulorhexis treatmentaccording to one embodiment of the present invention.

FIG. 10 illustrates a method for detecting and/or providing therapeutictreatment to an anatomical feature with an optical system according toone embodiment of the present invention.

FIG. 11 illustrates a method for analyzing the ophthalmic anatomy of apatient posterior to the cornea and/or for providing therapeutictreatment to the ophthalmic anatomy according to one embodiment of thepresent invention.

FIG. 12 illustrates a system for treating an eye of a patient accordingto one embodiment of the present invention.

FIG. 13 illustrates a representative image of the placement, centration,and uniform circularity of a laser-assisted capsulotomy relative to thepupil in a cadaver eye according to one embodiment of the presentinvention.

FIG. 14A illustrates a screen shot of a system used to measure thecorneal pachymetry and anterior chamber depth of a rabbit eye accordingto one embodiment of the present invention.

FIG. 14B illustrates a screen shot of a range-finding scan through thecorneal surface, lens surface, and internal structure of a lensaccording to one embodiment of the present invention.

FIG. 14C illustrates an image of a treated rabbit eye and an intraocularlens implant according to one embodiment of the present invention.

FIG. 15 illustrates an adapted optical system according to oneembodiment of the present invention.

FIG. 16 illustrates a focal quality of a beam passing through a liquidpatient interface with no cornea and with a cadaver cornea according toone embodiment of the present invention.

FIG. 17 illustrates a comparison of the effects of laser cutting in alens of ex-vivo pig eyes docked with a liquid patient interface (LI) anda flat applanating patient interface (FA) according to one embodiment ofthe present invention.

FIG. 18A illustrates an optical system according to an embodiment of thepresent invention which includes a polarization beam-splitter and aquarter-wave plate configured to generate circularly rotated polarizedlaser beams.

FIG. 18B illustrates an optical system according to another embodimentof the present invention which includes a Faraday rotator configured togenerate rotated polarized laser beams.

FIG. 19 illustrates an optical system according to yet anotherembodiment of the present invention, incorporating the simultaneous useof laser beams of different wavelengths, with one laser beam used formeasurement and a second laser beam used for delivering treatment.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention encompass methods and systems foranalyzing the ophthalmic anatomy of a patient posterior to the corneaand/or for providing therapeutic treatment to the ophthalmic anatomy.The method may include scanning a focus of a femtosecond laser beam (orother laser beam) along a path within the patient's eye. A portion ofthe path may be disposed at the corneal endothelium or posterior to thepatient's cornea and the path may include a first location and a secondlocation. The method may also include acquiring a first reflectanceimage associated with the focus disposed at the first location andacquiring a second reflectance image associated with the focus disposedat the second location. The method may further include determining thepresence or absence of an ophthalmic anatomical feature of the eye basedon a comparison between the first reflectance image and the secondreflectance image. The method may additionally include operating a laserbeam to provide therapeutic treatment to one or more of the anatomicalfeatures. The laser beam used in therapeutic procedures may be thefemtosecond laser used in the scanning process.

The first and second reflectance images may be acquired with a CCDcamera or any other type of camera or image capture device. Theanatomical feature may include a capsular bag and/or a lens within thecapsular bag. The therapeutic treatment provided by the laser (e.g., thefemtosecond laser) may include disrupting a capsule or lens. Thefemtosecond laser may be operated at a lower energy level during thescanning process and may be operated at a higher energy level to providethe therapeutic treatment.

In some embodiments, the therapeutic energy level of the femtosecondlaser beam may be maintained or provided during the scanning process inorder to provide the therapeutic treatment concurrent with or during thescanning process. In other words, the energy level of the femtosecondlaser beam may be varied between a lower energy level and a higherenergy level so that the therapeutic treatment and scan process may beperformed nearly simultaneously. For example, a lower energy level maybe used for the femtosecond laser beam to determine the location,orientation, and other properties of the capsular bag (or otheranatomical feature) and subsequently, a higher energy level may be usedto provide therapeutic treatment to the capsular bag (or otheranatomical feature). In other embodiments, the therapeutic treatment maybe provided while anatomical features are being scanned (i.e., duringthe scanning process).

The femtosecond laser beam signals/energy levels may be generated inresponse to differences in plasma formation when the focal point of thefemtosecond laser is scanned in the liquid vitreous between tissues ofthe eye and/or scanned within the tissues of the capsular bag, lens, orendothelial layers along the posterior of the cornea. In otherembodiments, therapeutic treatment may be provided subsequent to thescanning process.

The therapeutic treatments that may be performed with the femtosecondlaser include lens fragmentation, capsulorhexis, capsulotomy, and thelike. Capsulotomy procedures generally refer to procedures where thewhole or a portion of the capsule is removed. Capsulorhexis proceduresinvolve tearing or cutting away a portion of the capsule, and lensfragmentation procedures involve incising, disrupting, fragmenting,and/or breaking up the lens. Such treatments may be performed as part ofan extracapsular cataract extraction procedure (ECCE), or commonly acataract removal. The use of the femtosecond laser (or other laser) inthe lens fragmentation process may reduce or eliminate corneal stressthat may result from conventional phacoemulsification proceduresinvolving ultrasound vibrations and probes. Further, use of thefemtosecond laser in cataract removal procedures may provide theadvantage of smaller capsular incisions while reducing the operatorlearning curve required for conventional phacoemulsification proceduresusing ultrasound vibrations and probes. This may reduce post-cataractremoval complications.

Using the femtosecond laser and one or more therapeutic proceduresdescribed herein, the capsule may be incised for capsulotomy and/or thelens may be incised and broken into fragments prior to the capsulorhexisor laser capsulotomy, and vice versa, followed by insertion of a forcepor probe to withdraw the incised portion of the capsule and/or insertionof an aspiration probe to withdraw the severed portions of the lens. Thefemtosecond laser and system described herein may also be used for postcataract procedures, such as to cut or ablate clouded portions of thecapsule subsequent to an ECCE procedure. The therapeutic treatmentprovided by the femtosecond laser may be extended to include the backsurface of the lens making it possible to perform some pre-chop orcutting of the lens. Note that although this embodiment describes afemtosecond laser, other non-ultraviolet, ultra-short pulsed lasers withpulse durations as long as 3 nanoseconds and as short as 10 femtosecondsmay be used for the same therapeutic procedures. For instance,picosecond lasers may be used for similar incisions and procedures.

During the scanning process, the location, orientation (e.g., tilt),depth and the like of the capsule or lens within the eye may bedetermined. The focal point of the laser beam may be varied alongorthogonal x, y, and z axes during such scanning procedures. Varying thelaser beam's focal point in this manner and determining the location,orientation, and depth of anatomical features may be referred to asrange finding. The laser beams used in such operations may be referredto as range finding lasers. The scanning process may also replace otherpre-operative procedures, such as keratometry testing to determine thestrength of the intraocular lens (IOL) needed. Such testing may involvethe femtosecond laser, which may be set at a low/scanning energy level.

The methods and systems described herein involve ocular diagnostic(i.e., range finding) and therapeutic treatment techniques. Suchdiagnostic or range finding techniques involve directing laser lightfrom a femtosecond laser beam (or other laser source) to the eye inorder to locate ophthalmic anatomy posterior to the cornea (e.g.,capsular bag, lens, and the like). In therapeutic treatments, the lightfrom the same femtosecond laser beam (or other laser) may be focusedwithin the eye in order to disrupt tissue posterior to the cornea, andparticularly tissue of the capsular bag or crystalline lens. Thediagnostic applications of the femtosecond laser beam (i.e., rangefinding and/or therapeutic treatment) provided by the methods andsystems described herein may be used in conjunction with conventionalcataract removal systems and procedures, such as to range find variousophthalmic anatomy prior, during, or following such procedures.

In one embodiment, the laser light may be polarized. The polarized lightmay improve detection of the ophthalmic anatomy during diagnostic orrange finding applications. In a specific embodiment, the light iscircularly polarized rather than plane polarized. The circularlypolarized light may be simpler to implement versus plane polarizedand/or additionally improve detection of the ophthalmic anatomy duringthe diagnostic or range finding applications.

The crystalline lens or lens resides within the capsular bag, posteriorto the cornea. It is often desirable to incise and selectively remove aportion of the capsular bag and/or lens within the capsular bag, such asfor example during cataract surgery. According to embodiments of theinvention, prior to such procedures (e.g., cataract surgery), thecapsular bag and/or lens are located by scanning a femtosecond laserwithin the eye, and evaluating the resulting reflected light. Thereflected light is generated by the interface between tissue layers ofthe eye. In some embodiments, the femtosecond laser light used forlocating tissues (e.g., range finding) may be at a lower energy thanthat used for incising the capsular bag or lens.

In other embodiments, the scanning procedure and therapeutic proceduremay occur in real time or roughly simultaneously. For example, atherapeutic energy level may be maintained when locating tissues, withthe tissue identifying light signals being generated in response todifferences in plasma formation when the focal point of the laser isscanned in the liquid vitreous between tissues of the eye, and/orscanned within tissues of the capsular bag, lens, or endothelial layersalong the posterior of the cornea. In yet other embodiments, the energylevel may be varied between a scanning energy level and a therapeuticenergy level so that a therapeutic treatment (e.g., lens fragmentation,capsulorhexis, and the like) may be performed immediately after theophthalmic anatomy (e.g., capsular bag, lens, and the like) is located.

Optionally, techniques may involve using a zoom beam expander (ZBX) tomove the beam focal point throughout subcorneal depths, for examplebetween 0 and 6 mm, along the optical axis, and detecting any changes inthe index of refraction associated with corresponding reflected light.In some instances, results can be used to plan for capsulorhexis orcapsule disrupting procedures.

Embodiments of the present invention can be readily adapted for use withexisting laser systems and other optical treatment devices. Althoughsystem, software, and method embodiments of the present invention aredescribed primarily in the context of a laser eye surgery system, itshould be understood that embodiments of the present invention may beadapted for use in alternative eye treatment procedures, systems, ormodalities, such as spectacle lenses, intraocular lenses, accommodatingIOLs, contact lenses, corneal ring implants, collagenous corneal tissuethermal remodeling, corneal inlays, corneal onlays, other cornealimplants or grafts, and the like. Relatedly, systems, software, andmethods according to embodiments of the present invention are wellsuited for customizing any of these treatment modalities to a specificpatient. Thus, for example, embodiments encompass custom intraocularlenses, custom contact lenses, custom corneal implants, and the like,which can be configured to treat or ameliorate any of a variety ofvision conditions in a particular patient based on their unique ocularcharacteristics or anatomy.

Optical Systems

Turning now to the drawings, FIG. 1 illustrates a laser eye surgerysystem 10 of the present invention, including a laser 12 that produces alaser beam 14. Laser 12 is optically coupled to laser delivery optics16, which directs laser beam 14 to an eye E of patient P. A deliveryoptics support structure (not shown here for clarity) extends from aframe 18 supporting laser 12. A microscope 20 is mounted on the deliveryoptics support structure, the microscope often being used to image acornea of eye E.

Laser 12 may comprises a femtosecond laser capable of providing pulsedlaser beams, which may be used in optical procedures, such as localizedphotodisruption (e.g., laser induced optical breakdown). Localizedphotodisruptions can be placed at or below the surface of the materialto produce high-precision material processing. For example, amicro-optics scanning system may be used to scan the pulsed laser beamto produce an incision in the material, create a flap of material,create a pocket within the material, form removable structures of thematerial, and the like. The term “scan” or “scanning” refers to themovement of the focal point of the pulsed laser beam along a desiredpath or in a desired pattern.

To provide the pulsed laser beam, the laser 12 may utilize a chirpedpulse laser amplification system, such as that described in U.S. Pat.No. RE37,585, for photoalteration. U.S. Pat. Publication No.2004/0243111 also describes other methods of photoalteration. Otherdevices or systems may be used to generate pulsed laser beams. Forexample, non-ultraviolet (UV), ultra-short pulsed laser technology canproduce pulsed laser beams having pulse durations measured infemtoseconds. Some of the non-UV, ultra-short pulsed laser technologymay be used in ophthalmic applications. For example, U.S. Pat. No.5,993,438 discloses a device for performing ophthalmic surgicalprocedures to effect high-accuracy corrections of optical aberrations.U.S. Pat. No. 5,993,438 discloses an intrastromal photodisruptiontechnique for reshaping the cornea using a non-UV, ultra-short (e.g.,femtosecond pulse duration), pulsed laser beam that propagates throughcorneal tissue and is focused at a point below the surface of the corneato photodisrupt stromal tissue at the focal point. As explained before,other non-UV, ultra-short pulsed lasers (e.g. picosecond pulse duration)may be used.

The system 10 is capable of generating the pulsed laser beam 14 withphysical characteristics similar to those of the laser beams generatedby a laser system disclosed in U.S. Pat. Nos. 4,764,930, 5,993,438, orthe like. For example, the system 10 can produce a non-UV, ultra-shortpulsed laser beam for use as an incising laser beam. This pulsed laserbeam preferably has laser pulses with durations as long as a fewnanoseconds or as short as a few femtoseconds. For intrastromalphotodisruption of the tissue, the pulsed laser beam 14 has a wavelengththat permits the pulsed laser beam 14 to pass through the cornea withoutabsorption by the corneal tissue. The wavelength of the pulsed laserbeam 14 is generally in the range of about 3 microns to about 1.9 nm,preferably between about 400 nm to about 3000 nm, and the irradiance ofthe pulsed laser beam 14 for accomplishing photodisruption of stromaltissues at the focal point is greater than the threshold for opticalbreakdown of the tissue. Although a non-UV, ultra-short pulsed laserbeam is described in this embodiment, the laser 12 produces a laser beamwith other pulse durations and different wavelengths in otherembodiments.

In this embodiment, the delivery optics 16 direct the pulsed laser beam14 toward the eye (e.g., onto the cornea) for plasma mediated (e.g.,non-UV) photoablation of superficial tissue, or into the stroma forintrastromal photodisruption of tissue. The system 10 may also includean applanation lens (not shown) to flatten the cornea prior to scanningthe pulsed laser beam 14 toward the eye. A curved, or non-planar, lensmay substitute this applanation lens to contact the cornea in otherembodiments.

Laser system 10 will generally include a computer or programmableprocessor 22. Processor 22 may comprise (or interface with) aconventional PC system including the standard user interface devicessuch as a keyboard, a display monitor, and the like. Processor 22 willtypically include an input device such as a magnetic or optical diskdrive, an Internet connection, or the like. Such input devices willoften be used to download a computer executable code from a tangiblestorage media 29 embodying any of the methods of the present invention.Tangible storage media 29 may take the form of a floppy disk, an opticaldisk, a data tape, a volatile or non-volatile memory, RAM, or the like,and the processor 22 will include the memory boards and other standardcomponents of modern computer systems for storing and executing thiscode. Tangible storage media 29 may optionally embody wavefront sensordata, wavefront gradients, a wavefront elevation map, a treatment map, acorneal elevation map, and/or an ablation table. While tangible storagemedia 29 will often be used directly in cooperation with an input deviceof processor 22, the storage media may also be remotely operativelycoupled with processor by means of network connections such as theInternet, and by wireless methods such as infrared, Bluetooth, or thelike.

Laser 12 and delivery optics 16 will generally direct laser beam 14 tothe eye of patient P under the direction of a computer 22. Computer 22will often selectively adjust laser beam 14 to expose portions of thecornea to the pulses of laser energy so as to effect a predeterminedsculpting of the cornea and alter the refractive characteristics of theeye. In many embodiments, both laser beam 14 and the laser deliveryoptical system 16 will be under computer control of processor 22 toeffect the desired laser incising or sculpting process, with theprocessor effecting (and optionally modifying) the pattern of laserpulses. The pattern of pulses may by summarized in machine readable dataof tangible storage media 29 in the form of a treatment table, and thetreatment table may be adjusted according to feedback input intoprocessor 22 from an automated image analysis system in response tofeedback data provided from an ablation monitoring system feedbacksystem. Optionally, the feedback may be manually entered into theprocessor by a system operator. Such feedback might be provided byintegrating the wavefront measurement system described below with thelaser treatment system 10, and processor 22 may continue and/orterminate a sculpting treatment in response to the feedback, and mayoptionally also modify the planned sculpting based at least in part onthe feedback. Measurement systems are further described in U.S. Pat. No.6,315,413, the full disclosure of which is incorporated herein byreference.

Laser beam 14 may be adjusted to produce the desired incisions orsculpting using a variety of alternative mechanisms. The laser beam mayalso be tailored by varying the size and offset of the laser spot froman axis of the eye, as described in U.S. Pat. Nos. 5,683,379, 6,203,539,and 6,331,177, the full disclosures of which are incorporated herein byreference.

Still further alternatives are possible, including scanning of the laserbeam over the surface of the eye and controlling the number of pulsesand/or dwell time at each location, as described, for example, by U.S.Pat. No. 4,665,913, the full disclosure of which is incorporated hereinby reference; using masks in the optical path of laser beam 14 whichablate to vary the profile of the beam incident on the cornea, asdescribed in U.S. Pat. No. 5,807,379, the full disclosure of which isincorporated herein by reference; hybrid profile-scanning systems inwhich a variable size beam (typically controlled by a variable widthslit and/or variable diameter iris diaphragm) is scanned across thecornea; or the like. The computer programs and control methodology forthese laser pattern tailoring techniques are well described in thepatent literature.

Additional components and subsystems may be included with laser system10, as should be understood by those of skill in the art. Furtherdetails of suitable systems can be found in commonly assigned U.S.Publication Nos. 20090247997 and 20090247998, the complete disclosuresof which are incorporated herein by reference. Suitable systems alsoinclude commercially available femtosecond laser systems such as thosemanufactured and/or sold by Alcon, Technolas, Nidek, WaveLight, Schwind,Zeiss-Meditec, Ziemer, and the like.

The delivery optics 16 may include a scanner that operates at pulserepetition rates between about 10 kHz and about 400 kHz, or at any otherdesired rate. In one embodiment, the scanner generally moves the focalpoint of the pulsed laser beam 14 through the desired scan pattern at asubstantially constant scan rate while maintaining a substantiallyconstant separation between adjacent focal points of the pulsed laserbeam 14. The step rate at which the focal point of the laser beam 14 ismoved is referred to herein as the scan rate. The scan rates may beselected from a range between about 30 MHz and about 1 GHz with a pulsewidth in a range between about 300 picoseconds and about 10femtoseconds, although other scan rates and pulse widths may be used.Further details of laser scanners are known in the art, such asdescribed, for example, in U.S. Pat. No. 5,549,632, the entiredisclosure of which is incorporated herein by reference.

In one embodiment, the scanner utilizes a pair of scanning mirrors orother optics (not shown) to angularly deflect and scan the pulsed laserbeam 14. For example, scanning mirrors driven by galvanometers may beemployed where each of the mirrors scans the pulsed laser beam 14 alongone of two orthogonal axes. A focusing objective (not shown), (whetherone lens or several lenses), images the pulsed laser beam 14 onto afocal plane of the system 10. The focal point of the pulsed laser beam14 may thus be scanned in two dimensions (e.g., the x-axis and they-axis) within the focal plane of the system 10. Scanning along thethird dimension, i.e., moving the focal plane along an optical axis(e.g., the z-axis), may be achieved by moving the focusing objective, orone or more lenses within the focusing objective, along the opticalaxis.

FIG. 2 is a simplified block diagram of an exemplary computer system 22that may be used by the laser surgical system 10 of the presentinvention. Computer system 22 typically includes at least one processor52 which may communicate with a number of peripheral devices via a bussubsystem 54. These peripheral devices may include a storage subsystem56, comprising a memory subsystem 58 and a file storage subsystem 60,user interface input devices 62, user interface output devices 64, and anetwork interface subsystem 66. Network interface subsystem 66 providesan interface to outside networks 68 and/or other devices, such as thewavefront measurement system 30.

User interface input devices 62 may include a keyboard, pointing devicessuch as a mouse, trackball, touch pad, or graphics tablet, a scanner,foot pedals, a joystick, a touchscreen incorporated into the display,audio input devices such as voice recognition systems, microphones, andother types of input devices. User input devices 62 will often be usedto download a computer executable code from a tangible storage media 29embodying any of the methods of the present invention. In general, useof the term “input device” is intended to include a variety ofconventional and proprietary devices and ways to input information intocomputer system 22.

User interface output devices 64 may include a display subsystem, aprinter, a fax machine, or non-visual displays such as audio outputdevices. The display subsystem may be a cathode ray tube (CRT), aflat-panel device such as a liquid crystal display (LCD), a projectiondevice, or the like. The display subsystem may also provide a non-visualdisplay such as via audio output devices. In general, use of the term“output device” is intended to include a variety of conventional andproprietary devices and ways to output information from computer system22 to a user.

Storage subsystem 56 can store the basic programming and data constructsthat provide the functionality of the various embodiments of the presentinvention. For example, a database and modules implementing thefunctionality of the methods of the present invention, as describedherein, may be stored in storage subsystem 56. These software modulesare generally executed by processor 52. In a distributed environment,the software modules may be stored on a plurality of computer systemsand executed by processors of the plurality of computer systems. Storagesubsystem 56 typically comprises memory subsystem 58 and file storagesubsystem 60.

Memory subsystem 58 typically includes a number of memories including amain random access memory (RAM) 70 for storage of instructions and dataduring program execution and a read only memory (ROM) 72 in which fixedinstructions are stored. File storage subsystem 60 provides persistent(non-volatile) storage for program and data files, and may includetangible storage media 29 (FIG. 1) which may optionally embody wavefrontsensor data, wavefront gradients, a wavefront elevation map, a treatmentmap, and/or an ablation table. File storage subsystem 60 may include ahard disk drive, a floppy disk drive along with associated removablemedia, a Compact Digital Read Only Memory (CD-ROM) drive, an opticaldrive, DVD, CD-R, CD-RW, solid-state removable memory, and/or otherremovable media cartridges or disks. One or more of the drives may belocated at remote locations on other connected computers at other sitescoupled to computer system 22. The modules implementing thefunctionality of the present invention may be stored by file storagesubsystem 60.

Bus subsystem 54 provides a mechanism for letting the various componentsand subsystems of computer system 22 communicate with each other asintended. The various subsystems and components of computer system 22need not be at the same physical location but may be distributed atvarious locations within a distributed network. Although bus subsystem54 is shown schematically as a single bus, alternate embodiments of thebus subsystem may utilize multiple busses.

Computer system 22 itself can be of varying types including a personalcomputer, a portable computer, a workstation, a computer terminal, anetwork computer, a control system in a wavefront measurement system orlaser surgical system, a mainframe, or any other data processing system.Due to the ever-changing nature of computers and networks, thedescription of computer system 22 depicted in FIG. 2 is intended only asa specific example for purposes of illustrating one embodiment of thepresent invention. Many other configurations of computer system 22 arepossible having more or less components than the computer systemdepicted in FIG. 2.

Referring now to FIG. 3, one embodiment of a wavefront measurementsystem 30 is schematically illustrated in simplified form. In verygeneral terms, wavefront measurement system 30 is configured to senselocal slopes of a gradient map exiting the patient's eye. Devices basedon the Shack-Hartmann principle generally include a lenslet array tosample the gradient map uniformly over an aperture, which is typicallythe exit pupil of the eye. Thereafter, the local slopes of the gradientmap are analyzed so as to reconstruct the wavefront surface or map.

More specifically, one wavefront measurement system 30 includes an imagesource 32, such as a laser, which projects a source image throughoptical tissues 34 of eye E so as to form an image 44 upon a surface ofretina R. The image from retina R is transmitted by the optical systemof the eye (e.g., optical tissues 34) and imaged onto a wavefront sensor36 by system optics 37. The wavefront sensor 36 communicates signals toa computer system 22′ for measurement of the optical errors in theoptical tissues 34 and/or determination of an optical tissue ablationtreatment program. Computer 22′ may include the same or similar hardwareas the computer system 22 illustrated in FIGS. 1 and 2. Computer system22′ may be in communication with computer system 22 that directs thelaser surgery system 10, or some or all of the components of computersystem 22, 22′ of the wavefront measurement system 30 and laser surgerysystem 10 may be combined or separate. If desired, data from wavefrontsensor 36 may be transmitted to a laser computer system 22 via tangiblemedia 29, via an I/O port, via a networking connection 66 such as anintranet or the Internet, or the like.

Wavefront sensor 36 generally comprises a lenslet array 38 and an imagesensor 40. As the image from retina R is transmitted through opticaltissues 34 and imaged onto a surface of image sensor 40 and an image ofthe eye pupil P is similarly imaged onto a surface of lenslet array 38,the lenslet array separates the transmitted image into an array ofbeamlets 42, and (in combination with other optical components of thesystem) images the separated beamlets on the surface of sensor 40.Sensor 40 typically comprises a charged couple device or “CCD,” andsenses the characteristics of these individual beamlets, which can beused to determine the characteristics of an associated region of opticaltissues 34. In particular, where image 44 comprises a point or smallspot of light, a location of the transmitted spot as imaged by a beamletcan directly indicate a local gradient of the associated region ofoptical tissue.

Eye E generally defines an anterior orientation ANT and a posteriororientation POS. Image source 32 generally projects an image in aposterior orientation through optical tissues 34 onto retina R asindicated in FIG. 3. Optical tissues 34 again transmit image 44 from theretina anteriorly toward wavefront sensor 36. Image 44 actually formedon retina R may be distorted by any imperfections in the eye's opticalsystem when the image source is originally transmitted by opticaltissues 34. Optionally, image source projection optics 46 may beconfigured or adapted to decrease any distortion of image 44.

In some embodiments, image source optics 46 may decrease lower orderoptical errors by compensating for spherical and/or cylindrical errorsof optical tissues 34. Higher order optical errors of the opticaltissues may also be compensated through the use of an adaptive opticelement, such as a deformable mirror (described below). Use of an imagesource 32 selected to define a point or small spot at image 44 uponretina R may facilitate the analysis of the data provided by wavefrontsensor 36. Distortion of image 44 may be limited by transmitting asource image through a central region 48 of optical tissues 34 which issmaller than a pupil 50, as the central portion of the pupil may be lessprone to optical errors than the peripheral portion. Regardless of theparticular image source structure, it will be generally be beneficial tohave a well-defined and accurately formed image 44 on retina R.

In one embodiment, the wavefront data may be stored in a computerreadable medium 29 or a memory of the wavefront sensor system 30 in twoseparate arrays containing the x and y wavefront gradient valuesobtained from image spot analysis of the Shack-Hartmann sensor images,plus the x and y pupil center offsets from the nominal center of theShack-Hartmann lenslet array, as measured by the pupil camera 51 (FIG.3) image. Such information contains all the available information on thewavefront error of the eye and is sufficient to reconstruct thewavefront or any portion of it. In such embodiments, there is no need toreprocess the Shack-Hartmann image more than once, and the data spacerequired to store the gradient array is not large. For example, toaccommodate an image of a pupil with an 8 mm diameter, an array of a20×20 size (i.e., 400 elements) is often sufficient. As can beappreciated, in other embodiments, the wavefront data may be stored in amemory of the wavefront sensor system in a single array or multiplearrays.

While the methods of the present invention will generally be describedwith reference to sensing of an image 44, a series of wavefront sensordata readings may be taken. For example, a time series of wavefront datareadings may help to provide a more accurate overall determination ofthe ocular tissue aberrations. As the ocular tissues can vary in shapeover a brief period of time, a plurality of temporally separatedwavefront sensor measurements can avoid relying on a single snapshot ofthe optical characteristics as the basis for a refractive correctingprocedure. Still further alternatives are also available, includingtaking wavefront sensor data of the eye with the eye in differingconfigurations, positions, and/or orientations. For example, a patientwill often help maintain alignment of the eye with wavefront measurementsystem 30 by focusing on a fixation target, as described in U.S. Pat.No. 6,004,313, the full disclosure of which is incorporated herein byreference. By varying a position of the fixation target as described inthat reference, optical characteristics of the eye may be determinedwhile the eye accommodates or adapts to image a field of view at avarying distance and/or angles.

The location of the optical axis of the eye may be verified by referenceto the data provided from a pupil camera 52. In the exemplaryembodiment, a pupil camera 52 images pupil 50 so as to determine aposition of the pupil for registration of the wavefront sensor datarelative to the optical tissues.

An alternative embodiment of a wavefront measurement system isillustrated in FIG. 3A. The major components of the system of FIG. 3Aare similar to those of FIG. 3. Additionally, FIG. 3A includes anadaptive optical element 53 in the form of a deformable mirror. Thesource image is reflected from deformable mirror 98 during transmissionto retina R, and the deformable mirror is also along the optical pathused to form the transmitted image between retina R and imaging sensor40. Deformable mirror 98 can be controllably deformed by computer system22 to limit distortion of the image formed on the retina or ofsubsequent images formed of the images formed on the retina, and mayenhance the accuracy of the resultant wavefront data. The structure anduse of the system of FIG. 3A are more fully described in U.S. Pat. No.6,095,651, the full disclosure of which is incorporated herein byreference.

The components of an embodiment of a wavefront measurement system formeasuring the eye and ablations may comprise elements of a WaveScan®system, available from AMO MANUFACTURING USA, LLC, MILPITAS, Calif. Oneembodiment includes a WaveScan system with a deformable mirror asdescribed above. An alternate embodiment of a wavefront measuring systemis described in U.S. Pat. No. 6,271,915, the full disclosure of which isincorporated herein by reference. It is appreciated that any wavefrontaberrometer could be employed for use with the present invention.Relatedly, embodiments of the present invention encompass theimplementation of any of a variety of optical instruments provided byWaveFront Sciences, Inc., including the COAS wavefront aberrometer, theClearWave contact lens aberrometer, the CrystalWave IOL aberrometer, andthe like.

Optical Systems for Therapeutic and/or Diagnostic Scanning

Referring now to FIG. 4, illustrated is an optical system 400 accordingto one embodiment of the present invention. In some embodiments theoptical system corresponds to an Intralase laser system or other lasersystem. Optical system 400 includes a laser source 402 that emits alaser beam. Laser light exiting laser source 402 may pass through amirror path (not shown). The laser light may then be passed to a beamexpander module 404. Beam expander module 404 may have a variable powerthat may range from about 2× to about 5× so that the system can be tunedto the laser parameters of the particular laser source 402. In oneembodiment, beam expander module 404 is variable between about 2.8× andabout 4×. In another embodiment, beam expander module 404 comprises apower of about 2×.

Optical system 400 may also include galvo block module 406. In oneembodiment, galvo bock module 406 includes 2 mirrors that provide twodimensional scanning of the laser beam: one for x axis motion of thelaser beam and one for y axis motion of the laser beam. In anotherembodiment, galvo block module 406 includes 3 mirrors, which operate tokeep the laser beam centered as the laser beam exits galvo block module406 and/or enters the next assembly. Optical system 400 may furtherinclude zoom beam expander 408. In some embodiments zoom beam expander408 has a 6× power, which expands the laser beam by a factor of 6. Inaddition, zoom beam expander 408 may have a large field of view on theinput side. Beam expander module 408 may function similar to an afocaltelescope. Elements within zoom beam expander 408 may be adjustable toallow the depth of a laser beam's focal point to be adjusted a distanceX along the optical axis (i.e., allow z axis scanning) The adjustableelements may include a doublet lens that provides a 150 mm focal length.The laser beams' focal point may be adjusted or varied a distance Xalong the optical axis between a first anatomical feature 414 (e.g.,capsule, cornea, and the like) and a second anatomical feature 416(e.g., lens). In some embodiments, the variable distance X rangesbetween 0 and 6 mm, although others depths are possible. Such variancemay allow the focal point of the laser beam to be adjusted from abovethe top of the cornea to a position below the lens. In otherembodiments, the focal point depth may be adjusted to deeper depths,such as posterior to the capsule and/or retina.

In addition to varying the depth of the focal point, zoom beam expander408 may also correct or compensate for aberrations to maintain the laserbeam focal spot quality. Correcting or compensating for aberrations mayinvolve the application of an applanation lens as described herein orapplication or different optics configurations. Further details ofsuitable systems or optical configurations can be found in U.S.Publication Nos. 20110028948, 20110028949, 20110028950, 20110028951,20110028952, 20110028953, 20110028954, 20110028955, 20110028957, and20110028958, the complete disclosures of which are incorporated hereinby reference.

In another embodiment, zoom beam expander 408 may not vary the depth ofthe focal point. Rather, additional optics (not shown) may be removablycoupled with optical system 400 to vary the depth of the laser beam'sfocal point and/or provide lens fragmentation, capsulorhexis,capsulotomy, and/or other therapeutic treatments. The additional opticsmay have a lower depth variance range, such as 2-4 mm, although a fulldepth range of motion may be provided in some embodiments. Theadditional optics may be removed when the diagnostic scan and/ortherapeutic treatment is complete so that other procedures may beperformed, such as corneal flap cutting.

Optical system 400 may additionally include a focusing objective 410,which receives collimated light from zoom beam expander 408. Focusingobjective 410 focuses the laser beam to a focal point via lens 412. Thespot size of the focused laser beam may be variable. In someembodiments, the spot size may vary between 1 and 5 microns. In otherembodiments, the spot size may be about 1.2 microns.

Some embodiments may involve performing a surgical or therapeuticprocedure on anatomical features of the eye, such as the lens, capsule,and the like. Surgical or therapeutic procedures may involvecapsulotomy, capsulorhexis, lens fragmentation, or other procedures.Capsulorhexis may involve incising a portion of the capsule to removethe lens and/or incising a portion of the capsule for removal. Lensfragmentation may include incising, breaking up, or disrupting a portionof the lens or the entire lens. The incision may be performed with afemtosecond laser, eliminating the need for a surgeon to manually cutaway portions of the capsule or use ultrasound probes to break up thelens. The femtosecond laser beam may be operated at high energy levelsduring such therapeutic procedures. For example, depending on the pulsewidth, the pulse energy can be between about 0.01 microJoules to about50 microJoules.

The femtosecond laser may also be operated in range finding proceduresto scan the interior of a patient's eye to determine a location, depth,and/or orientation of the lens, capsule, and/or other anatomicalfeature. The femtosecond laser beam is typically operated at low energylevels during range finding/diagnostic scanning procedures such that thefemtosecond energy imparted to the specific ocular tissue or fluid atthe focus of the beam is less than the plasma generation threshold orphotodisruption threshold for the specific ocular tissue or fluid (e.g.,capsular bag, lens, aqueous humor, cornea, and the like), morepreferably less than the energy threshold for bubble formation in thespecific ocular tissue or fluid, and even more preferably at a fractionof the energy threshold for bubble formation in the specific oculartissue or fluid (e.g., about ten percent (10%) of the energy thresholdfor bubble formation in the specific ocular tissue or fluid). In otherembodiments, range finding/diagnostic scanning can be performed whilethe femtosecond laser beam is operated at energy levels for performingsurgical or therapeutic procedures (e.g., greater than thephotodisruption threshold). Range finding or scanning the eye's interiormay involve moving a focus of the femtosecond laser beam (or other laserbeam) along a path within the patient's eye. A portion of the path orthe entire path may be disposed posterior to the patient's cornea andthe path may include a plurality of locations along the path that arescanned. Scanning the interior of the eye (i.e., range finding) mayprovide a 2D or 3D image of anatomical features within the eye. Imagesof the eye may be captured by a camera, such as the CCD camera describedherein. Range finding or diagnostic scanning may be performed prior toor concurrent with surgical or therapeutic procedures, such ascapsulorhexis, lens fragmentation, capsulotomy, and the like. Rangefinding, and specifically the variable depth of the laser beam's focalpoint, may allow both the back and front surface of the lens, capsule,and/or other anatomical feature to be mapped.

The therapeutic and/or diagnostic scanning procedures described hereinmay be provided in a field upgrade unit that may be removably coupledwith pre-existing laser optical systems. The field upgrade unit mayallow both diagnostic scanning and therapeutic procedures to beperformed on a pre-existing laser optical machine. The field upgradeunit may include a lens, camera, and semi-transparent mirror, such asmirror 612, lens 606, and camera 602 of FIG. 6A. The field upgrade unitmay be retrofitted to pre-existing laser optical systems. Fieldretrofitting may involve a turret between components of the opticalsystem or may be seamlessly fit in-line with other components of theoptical system.

FIGS. 5A and B illustrate an example of a range finding or diagnosticscanning procedure performed to identify anatomical features of the eye.FIG. 5A illustrates that the optical system may be used to determine alocation and/or orientation of a capsular bag 502 within eye 500.Specifically, an ophthalmic measurement device 504 (e.g., scanner and/ordetection device) may receive laser light reflected from capsular bag502 to determine conditions associated with the capsular bag 502. Forexample, ophthalmic measurement device 504 may determine that capsularbag 502 and/or a lens (not shown) comprise a tilted orientation.Similarly, ophthalmic measurement device 504 may determine a depth ofcapsular bag 502 and/or lens within the eye. Based on these detectedconditions, one or more therapeutic treatments (e.g., capsulorhexis,lens fragmentation, capsulotomy, and the like) may be calculated and/oradjusted to account for the location, tilt, and/or depth of capsular bag502 and/or the lens. The optical system may then be used to provide suchtreatments.

In one embodiment, the laser light may be polarized. The polarized lightmay be used during the range finding or diagnostic scanning procedure,although in some embodiments, the polarized light is additionally oralternatively used during therapeutic procedures. The polarized lightmay improve identification of anatomical features of the eye during therange finding or diagnostic scanning procedure. In a specificembodiment, the light is circularly polarized rather than planepolarized, which may improve implementation of the polarized lightand/or identification of the anatomical features of the eye.

FIG. 18A illustrates an optical system 1800 a according to oneembodiment of the present invention, which utilizes polarized laserbeams. Use of polarized laser beams by optical system 1800 a, andspecifically, of circular polarized laser beams, improves identificationof anatomical features of the eye, such as depth measurement of theanterior chamber of the eye. Polarized laser beams are also particularlyuseful for performing precise measurements of small amounts ofback-reflected/scattered light from tissues or objects under examinationthat exhibit low reflectivity. Optical system 1800 a includes a laser1832 that directs laser light toward the eye. In certain embodiments,the laser 1832 may be a non-ultraviolet, ultra-short pulsed laser withpulse durations between 10 femtoseconds and 3 nanoseconds, and awavelength between about 300 nm and 3000 nm. The laser beam generated bythe laser 1832 is transmitted through a polarization beam-splitter 1860that is configured to allow the passage of laser beams polarized in aspecific orientation, such as, e.g., vertical or horizontal. Thelinearly polarized laser beam is subsequently transformed into acircular polarized laser beam when it is transmitted through aquarter-wave plate 1862, with the rotation being in a first direction,i.e., either clockwise or counter-clockwise, depending on theorientation of the quarter-wave plate 1862. The circular polarized laserbeam travels from the quarter-wave plate 1862 and is directed toward anobjective 1810 by a mirror or reflective component 1866. The objective1810 focuses the laser beam to a focal point via an objective lens 1812.In the optical system 1800 a according to the embodiment shown in FIG.18A, a liquid patient interface 1864 is provided between the objective1810 and the eye. As described in paragraph [00123] and FIG. 16, theliquid patient interface 1864 may include a solution containing balancedsalt solution (BSS) or dextran, such as, for example, a 15% dextransolution.

Turning again to FIG. 18A, the laser beam is then reflected back towardthe quarter-wave plate 1862 and the polarization beam-splitter 1860.When the laser beam is back-reflected toward the quarter-wave plate 1862by the eye, the circular polarized laser beam changes in rotation to adirection opposite to that of the first direction of the laser beam whenit traveled toward the eye. For example, the rotation of the circularpolarized laser beam changes to a clockwise direction if the circularrotation of the polarized laser beam was counter-clockwise when ittraveled toward the eye. Similarly, the rotation of the circularpolarized laser beam would change to a counter-clockwise direction ifthe polarized laser beam was rotating in a clockwise direction when ittraveled toward the eye. As a result of the change in the direction ofthe rotation, as the back-reflected laser beam is transmitted and passesthrough the quarter-wave plate 1862, the laser beam is transformed intoa linearly polarized laser beam that is perpendicular in orientationrelative to the orientation of the laser beam that traveled toward theeye between the polarization beam-splitter 1860 and the quarter-waveplate 1862. The linearly polarized, back-reflected laser beam is thentransmitted to the polarization beam-splitter 1860. Because the linearlypolarized, back-reflected laser beam is now perpendicular in orientationrelative to the orientation of the laser beam as it traveled toward theeye, the back-reflected laser beam does not pass through thepolarization beam-splitter 1860 toward the laser 1832. Instead, it isreflected to a photo-detector 1802. Embodiments of optical system 1800 amay utilize a CCD camera or a sensitive photodiode or a quadrantdetector as the photo detector 1802. As shown in FIG. 18A, opticalsystem 1800 a incorporates a confocal system that includes a lens 1806and a pinhole 1868. The confocal system is placed in the back-reflectedlaser beam's direction of travel, in front of the photo detector 1802,so as to reduce optical background signal/noise. In an alternativeembodiment for optical system 1800 a, a Shack-Hartmann wavefront sensormay be substituted for lens 1806, pinhole 1868, and photo detector 1802.For any of the aforementioned embodiments, the photo detector 1802 (orShack-Hartmann wavefront sensor) may then communicate signalscorresponding to the back-reflected laser beam to a suitable computersystem, such as that shown in FIG. 2, for further processing.

In optical system 1800 a, substantially all of the back-reflected laserbeam is directed to the photo detector 1802. Additionally, thepolarization beam-splitter 1860 and the quarter-wave plate 1862 may beoptionally and temporarily removed from the optical system 1800 a whenthe laser 1832 of the system 1800 a is used to deliver therapeutictreatment to the eye. Temporary removal of the polarizationbeam-splitter 1860 and the quarter-wave plate 1862 from the opticalsystem 1800 a during a treatment procedure may be desirable if a userwishes to reduce the level of energy required for the desired treatment.

FIG. 18B depicts an optical system 1800 b that incorporates a Faradayrotator subsystem 1880 instead of the combination of a polarizedbeam-splitter 1860 and a quarter-wave plate 1862 used by optical system1800 a shown in FIG. 18A. As illustrated in FIG. 18B, the Faradayrotator subsystem 1880 includes a polarization beam-splitter 1882 and aFaraday rotator 1884, with the polarization beam-splitter 1882 locatedbetween the laser 1832 and the Faraday rotator 1884. In a secondembodiment, the Faraday rotator subsystem 1880 is a Faraday opticalisolator that includes a first polarizer, a Faraday rotator, and asecond polarizer. In this second embodiment, the first polarizer facesthe laser 1832, while the Faraday rotator is disposed between the firstpolarizer and the second polarizer, and the second polarizer faces theeye.

In optical system 1800 b as illustrated in FIG. 18B, the polarizationbeam-splitter 1882 of the Faraday rotator subsystem 1880 allows a laserbeam that is polarized in a first linear direction to be transmitted andto pass through. A laser beam that is polarized in that first lineardirection is transmitted through the Faraday rotator 1884, which rotatesthe laser beam by 45 degrees as the laser beam travels through theFaraday rotator subsystem 1880 towards the eye. As the back-reflectedlaser beam travels away from the eye and through the Faraday rotatorsubsystem 1880, the polarization of the laser beam is again rotated by45 degrees by the Faraday rotator 1884. Thus, a laser beam that travelsthrough the Faraday rotator 1884 in the forward direction as well as theback-reflected direction will be rotated a total of 90 degrees (—i.e.will be perpendicular in orientation—) relative to the first lineardirection of polarization of the laser beam that was transmitted throughthe polarization beam-splitter 1882 in the forward direction toward theeye.

Because the laser beam is now polarized perpendicularly relative to thefirst linear direction of the laser beam and is thus, perpendicular tothe alignment of the polarization beam-splitter 1882 of the Faradayrotator subsystem 1880, the back-reflected laser beam is deflectedtoward the photo detector 1802 instead of being transmitted through tothe laser 1832. Optical system 1800 b may utilize a CCD camera or asensitive photodiode or a quadrant detector as the photo detector 1802.In other embodiments, the lens 1806, pinhole 1868, and photo detector1802 may be replaced with a Shack-Hartmann wavefront sensor.

As with optical system 1800 a, the photo detector 1802 or theShack-Hartmann wavefront sensor communicates signals corresponding tothe back-reflected laser beam to a suitable computer system, such asthat depicted in FIG. 2, which processes the signal data. Similar tooptical system 1800 a that includes a polarization beam-splitter with aquarter-wave plate, the optical system 1800 b, is able to directsubstantially all of the back-reflected laser beam to the photo detector1802 by using a Faraday rotator subsystem 1880 to isolate the incidentand reflected laser beams. When the laser 1832 of the optical system1800 b is used to deliver a therapeutic treatment to the eye and isoperated at an energy level sufficient to provide the desired treatment,the Faraday rotator subsystem 1880 does not need to be removed from thesystem 1800 b. Incorporating the Faraday rotator subsystem 1880 inoptical system 1800 b enables a user to apply a lower level of energy toprovide the same treatment than would be required with the opticalsystem 1800 a having the polarization beam-splitter 1860 and thequarter-wave plate 1862 intact.

FIG. 19 depicts another embodiment showing an optical system 1900 thatuses laser beams of different wavelengths, one to conduct measurementsand another to deliver treatment during a single ophthalmic procedure.Using one laser beam having one wavelength for therapeutic purposes andanother beam having a different wavelength for measuring an anatomicalfeature of the eye enables the optical system 1900 to provide increaseddetail when measuring anatomical features without having to compromiseon the strength of the laser beam used for therapeutic purposes. To thatend, optical system 1900 includes a first laser 1932 and a second 1970.The first laser 1932 generates a laser beam of sufficient strength toenable therapeutic procedures, whereas the second laser 1970 generates alaser beam intended to acquire increased details of an anatomicalfeature of the eye being analyzed. The first laser 1932 is thereforeconfigured to generate a laser beam that has a longer wavelength thanthe laser beam generated by the second laser 1970. In certainembodiments, the first laser 1932 may be a non-ultraviolet, ultra-shortpulsed laser with pulse durations as long as 3 nanoseconds and as shortas 10 femtoseconds, and a wavelength between about 300 nm to about 3000nm. When reflected back from the subject anatomical feature, the shorterwavelength laser beam generated by the second laser 1970 produces morescattering data relative to the longer wavelength laser beam from thefirst laser 1932, and thus, provides more details on the anatomicalfeature. In one implementation, for example, the optical system 1900 maybe configured such that the first laser 1932 generates a laser beam witha wavelength that is approximately 1053 nm for therapeutic purposes, andthe second laser 1970 generates a laser beam with a wavelength that isapproximately 780 nm for measurement purposes. In alternativeembodiments, the optical system 1900 may be configured such that thefirst laser 1932 generates a laser beam with a wavelength of betweenapproximately 300 nm to 3000 nm for therapeutic purposes, while thesecond laser 1970 generates a laser beam with a wavelength of betweenapproximately 450 nm to 990 nm.

Optical system 1900 includes a beam splitter 1972 that reflectsapproximately 50% of the laser beam from the second laser 1970 towardthe eye, while the remaining portion of the laser beam is transmittedand passes through to a beam dump 1974. The beam dump 1974 is configuredto absorb the excess energy that is not reflected toward the eye by thebeam-splitter 1972. The portion of the laser beam from the second laser1970 that is reflected by the beam-splitter 1972 is then directed towardthe eye by a dichroic mirror 1976. As shown in FIG. 19, the dichroicmirror 1976 is configured to reflect the laser beam from the secondlaser 1970 while also transmitting the laser beam generated by the firstlaser 1932. The laser beams from the first laser 1932 and the secondlaser 1970 are then reflected toward the eye by a mirror or reflectivecomponent 1966. Optical system 1900 incorporates an objective 1910,which includes an objective lens 1912 to focus the laser beams to afocal point in the eye. Additionally, a liquid patient interface 1964,which may include a solution containing BSS or dextran, may be disposedbetween the objective 1910 and the eye.

The laser beam that originated from the second laser 1970 is reflectedback toward the dichroic mirror 1976, which in turn reflects it towardthe beam-splitter 1972. The beam-splitter 1972 transmits approximately50% of this back-reflected laser beam toward a photo detector 1902,which may comprise, for example, a CCD camera, a sensitive photodiode,or a quadrant detector. As shown in FIG. 19, optical system 1900incorporates a confocal system including a lens 1906 and a pinhole 1968in order to focus the back-reflected laser beam and to reduce opticalbackground signal/noise. In another embodiment for optical system 1900,a Shack-Hartmann wavefront sensor is substituted for lens 1906, pinhole1968, and photo detector 1902. In any event, the photo detector 1902 orShack-Hartmann wavefront sensor then communicates signals correspondingto the back-reflected laser beam to any computer system suitable forprocessing that data, including for example, the system shown in FIG. 2.

Turning to FIG. 5B, FIG. 5B illustrates an embodiment of measuring theorientation, location, depth, and/or other conditions of an anatomicalfeature of the eye 520. The eye 520 may have a substantially flattenedcornea 524 with a lens 522 positioned posterior to cornea 524. Cornea524 may be flattened due to the application of an applanation lens (notshown) to the cornea. Although cornea 524 is shown having a flattenedconfiguration, it should be realized that cornea 524 may comprisevarious other configurations (e.g., round and the like). Lens 522 may betilted with respect to cornea 524. Lens 522 may be scanned with theoptical system to determine the amount of tilt, position, and/or depthof lens 522. The tilted orientation of lens 522 may be determined byvarying the depth of the focal point 530 of laser beam 532 along theoptical axis and scanning laser beam 532 across lens 522. For example,the depth and location of a first position 526 toward an exterior edgeof lens 522 may be measured by scanning the focal point 530 of laserbeam 532 to the first position 526. Laser light may be reflected at thefirst position 526 and detected by an ophthalmic measurement device 504to determine that the focal point 530 of laser beam 532 is at or near anexterior edge of lens 522.

Similarly, the focal point 530 of laser beam 532 may be scanned to asecond position 528 toward an opposite exterior edge of lens 522. Sincethe focal plane of laser beam 532 is planar, the focal point position isscanned from the focal plane associated with the first point 526 to thefocal plane associated with point 528 (shown by the arrow) via afocusing objective or other device. The depth and location of the secondposition 528 may be measured by laser light reflected to the scanner ordetection system 504 from second position 528. Other positions of lens522 may similarly be measured. The tilt, depth, position, and otherproperties of lens 522 may be determined based on the measured first andsecond positions, 526 and 528, and/or other positions of lens 522.

In one embodiment, varying the depth and position of the focal point 530of laser beam 532 may include scanning a ring field. The focal point 530of laser beam 532 may be scanned in a corkscrew pattern where laser beam532 is scanned in a circular pattern and the depth is reduced (orincreased) incrementally for subsequent circles. At some point the focalpoint 530 will intersect first position 526 and second position 528 andother positions on the surface of lens 522. The positions may each bemeasured and recorded.

In some embodiments, therapeutic procedures may be provided as laserbeam 532 is moved in the corkscrew pattern or other pattern. Forexample, laser beam 532 may be at a sufficiently high irradiance atfocal point 530 to cause material breakdown. As the focal point 530intersects with the capsule and the capsule is scanned, capsulorhexismay occur. Lens fragmentation, capsulotomy, and/or other therapeutictreatments may likewise be performed.

Referring now to FIG. 6A, illustrated is an embodiment of an opticalsystem 600 capable of scanning/mapping anatomical features of an eyeand/or providing therapeutic treatment thereto. Optical system 600includes a camera 602, such as a CCD camera, that captures images (660of FIG. 6B) of anatomical features 604 of the eye. Camera 602 may alsorepresent a sensitive photodiode or quadrant detector, which may providefaster, more sensitive, and less expensive image capture than a CCDcamera, or a Shack-Hartmann wavefront sensor. A beam splitter can beused to couple out light for camera 602. The arrows on laser beam 632indicate that laser beam 632 is focused on an anatomical feature 604 ofthe eye and that some laser light is reflected back to camera 602through lens 606. Mirrors 608 represent two axis tilting galvo mirrors,although other galvo mirror configurations are possible (e.g., 3 galvomirror configuration). Optical system 600 may include additional mirrorsas well.

Light emitted by the femtosecond laser (or other laser) is collected andcollimated by the objective 610 and/or zoom beam expander 614. The laserbeam is focused at focal point 620 within or on a surface of the eye. Aportion of the light that is reflected back is transmitted throughmirror 612 and focused by lens 606 onto camera 602. In some embodiments10% of the reflected light is transmitted through mirror 612, althoughmore or less light, such as 1%, may be transmitted. In one embodiment,lens 606 comprises an f=100 L2 lens that produces a spot size on camera602 of approximately 30 μm and a depth of field of about ±0.3 mm. Thesenumbers, however, are merely exemplary and do not limit the invention inany way.

The focal position 620 of laser beam 632 may be scanned or moved bycontrolling galvo mirrors 608, zoom beam expander 614, and/or objective610. Movement of the focal position 620 is illustrated by the arrowsadjacent focal position 620, which illustrates that focal position 620may be scanned horizontally as well as vertically (i.e., may be scannedalong orthogonal x, y, and z axes). As mentioned previously, some laserlight is reflected back from anatomical feature 604, transmitted throughmirror 612, and captured by camera 602. The light captured by camera 602forms a single spot (i.e., focal spot 662 of FIG. 6B). This may be aconjugated plane. The focal plane of the laser may be changed bychanging the scan lens or by other means. The focal plane may changealong Z axis, but will usually come back to a focal spot 662 on camera.When the focal position 620 intersects tissue, some light is usuallyreflected. The reflected light may come to a focus (i.e., focal spot662) back at the camera and the tissue of anatomical feature 604 atfocal position 620 may be imaged (660 of FIG. 6B). The color, shape, andintensity of the spot on camera 602 will vary depending on whether focalposition 620 is located at the aqueous humor, the capsule, the lens, andthe like (spots 662 and 664 represent different spot shapes, colors, andintensities of imaged light representing various ophthalmic features).In this manner the location of each anatomical feature may be determinedor measured and an appropriate therapeutic procedure may be determinedand/or applied. A Z encoder signal of objective 610 may provide thedepth of the cut in microns. The spot 662 on camera 602 may not moveduring x and y scanning of the pattern if camera 602 in the focal planeof lens 606.

Mirror 612 may be a partially silvered galvo mirror, or in someembodiments may include a multilayer dielectric stack. Laser light maybe reflected back to camera 602 and imaged 660 when the index ofrefraction of the material at focal position 620 changes, such as when adifferent material is encountered, a surface of the material isencountered, and the like. As described herein, the focal position 620may be driven along the optical axis, such as in the 3-6 mm or morerange. If a surface interface (e.g. tissue surface interface) is atfocal position 620, then a focal spot 662 may be produced on image 660and captured by camera 602. If a surface interface is not at focalposition 620, a slightly enlarged spot 664 may be produced and/ordetected. The enlarged spot 664 will generally have a lower totalirradiance (e.g. watts per square centimeter), but the same total power.The enlarged spot 664 represents an out of focus spot and indicates thatfocal position 620 is not at a surface interface of an anatomicalfeature.

In some embodiments, if the focal position 620 is focused on an opticalinterface, the back-reflected beam is also focused onto camera 602. Thespot size on camera 602 may be about 30 μm. If the focal position 620 isfocused above or below the surface, such as by 60 μm, the spot size oncamera 602 may be about 60 μm. Such an embodiment may allow depthmeasurements within an accuracy of about 3-5 μm and may provide anauto-z that compensates for cone height manufacturing errors.

As the focal position 620 is driven, such as from 0 to 6 mm, and morecommonly 3 to 6 mm, a sensor (not shown) may indicate the focal positiondepth. A correlation may be made for the focal position 620 whenscanning in x, y, and z directions, for example, each pulse of the laserbeam may be correlated with an x, y, and z position. When scanningthrough a volume, every time a camera frame is obtained (i.e., image660), it may be possible to know the x, y, and z position of thecaptured image 660. In this way, detection of a tissue surface (e.g.,capsule, lens, cornea, and the like) is possible. The data on thelocation may be determined, in part, from knowledge of the location ofthe system and the laser beams focus. In this manner, it is possible todetermine the configuration at any point in time. Data for camera framesmay be acquired and correlated to where the laser beam is focused (e.g.the query location). Each frame (i.e., image 660) may have an x, y, zlocation associated with it.

The captured image 660 and corresponding location may be analyzed todetect anatomical features 604 and/or properties of the anatomicalfeature (e.g., tilt, surface location, depth, and the like). Forexample, as described herein, bright spot or focal spot 662 may beproduced or detected in captured image 660 at a tissue surface at the x,y, and z location. An entire database of captured images 660 may beanalyzed to find focal/bright spots 662. The x, y, and z locationscorresponding with the focal/bright spots 662 may then be mapped toprovide a 3-dimensional image of one or more anatomical features 604 ofthe eye, such as the capsule, lens, cornea, and the like. Anatomicalfeatures 604 may thus be identified and the location and/or orientationof those features may be mapped in 3D space.

If the focal position 620 is positioned on an interface, such ascon-glass/air, cone-glass/cornea, cornea/aqueous, aqueous/capsule, andthe like, a sharp focal spot 662 may appear on camera 602. Thereflectivity of the different interfaces may be approximately: Coneglass/air=3.4%, Cone glass/cornea=0.61%, Cornealaqueous=0.034%, andAqueous/capsule=0.19%. The depth of the aqueous/capsule interface can bemeasured as well.

Scanning or imaging the eye in this manner may be done using a helicalscan, a raster scan, or any other type or pattern of scan. A helicalscan may involve mapping out a cylinder volume of the eye. In someembodiments, a volume of the eye may be scanned according to apredefined pattern, such as a raster or helical scan at a selectedpitch. As the volume of the eye is scanned, focal/bright spots 662corresponding to tissue surfaces may be detected. As tissue surfaces aredetected throughout the scanned volume, tissue shapes may be determinedor calculated and measured. Thus, various anatomical features 604 of theeye may be detected and measured. Scanning and imaging or mappinganatomical features 604 of the eye may be performed at a low power orscanning energy level, as previously discussed hereinabove, based on theoperating laser spot size and pulse width and the specific ocular tissuebeing scanned, imaged, or mapped.

In some embodiments, a fluorescence effect of the tissue of anatomicalfeature 604 at focal position 620 may also be obtained instead of or inaddition to the reflected image 660 captured by camera 602. To obtain afluorescence effect, the optical system may need to be corrected forcolor change. If the scanning/measurement process is based onfluorescence, the optical system may need adjusting based on laserwavelength and/or fluorescence wavelength.

Using the optical system and femtosecond laser described herein to rangefind (i.e., scan and map) anatomical features of the eye may ensure thatdelivered therapeutic laser energy remains away from the cornea. Forexample, the location and orientation of the lens may be determined sothat ablation energy from the femtosecond laser can be delivered to thelens to remove and/or disrupt it. The optical system may deliverablation energy during a therapeutic treatment concurrent with orclosely after range finding (i.e., a scanning and mapping operation).For example, an anatomical feature (e.g., lens) may be located andmeasured to determine the orientation and depth, and then ablationenergy may be delivered to the anatomical feature. Delivering ablationenergy may involve increasing the energy level of the scanning laser toa therapeutic level. Alternatively or additionally, other scans may bepossible, for example changing the shape and/or orientation of theanatomical feature, increasing the laser beam energy, and performing acapsulorhexis scan.

In some embodiments, the location of the changes to the optical systemmay be determined. For example, there may be changes concentrated in the6× beam expander, to obtain an additional 3-6 mm of depth. The scanningprocedures described herein may be performed with laser beam intensitiesthat do not cause optical damage to the cone glass. Similarly, depthmeasurements of the capsule may be taken without causing optical damageto the capsule.

In some cases, the optical system can be used for flap cutting inaddition to range finding/diagnostic scanning (i.e., anatomical imagingand mapping) and therapeutic treatment (e.g., capsulorhexis,capsulotomy, and/or lens fragmentation). For example, FIG. 7 illustratesthe femtosecond laser (or other laser) of the optical system being usedto incise the cornea to cut a flap. The femtosecond laser may be used tomake arcuate or other incisions in the cornea, which incisions may becustomized, intrastromal, stable, predictable, and the like. Likewise,corneal entry incisions may be made, which are custom, multi-plane, andself-sealing. In addition, the optical system described herein may beused to provide laser cataract surgery in the cornea. Such proceduresmay be provided using the flexibility of incisional software and rangefinding. The optical system may be used for precision locating of theanterior corneal surface with a hard or liquid interface.

In some embodiments, the optical system may be used to provide asecondary check, such as to obtain a finer resolution on anatomicalfeature surface depths by comparing spot sizes of different images(e.g., before and after signals). Similarly, comparing spot sizes ofdifferent images (e.g., before and after signals) may increaseresolution of the image. For example, a 5× increase in resolution may bepossible.

Referring now to FIG. 12 illustrated is a system 1200 for treating aneye 1210 of a patient. The eye 1210 includes a fluid posterior to acornea. System 1200 includes a femtosecond laser 1202 configured fordirecting femtosecond energy along a path. System 1200 also include anoptical system 1204 disposed along the path from the laser. Opticalsystem 1204 includes a focusing lens 1206 and a scanner 1208 so as toscan a focus 1212 of the femtosecond energy along a path within thepatient's eye 1210. The path may extend posterior to the patient'scornea within the fluid so that the path includes a first location 1214disposed within a tissue of the eye and a second location 1216 disposedwithin the cornea. In some embodiments, the focus 1212 imparts asufficient amount of energy to the particular tissue of the eye 1210such that a plasma is generated. For example, the femtosecond energyimparted to the particular tissue of the eye 1210 at the focus 1212 issufficient for photodisruption of the same tissue. In other embodiments,the femtosecond energy imparted to the particular tissue or fluid of theeye 1210 at the focus 1212 is less than the plasma generation thresholdcorresponding to the same tissue or fluid. For example, as previouslymentioned hereinabove, the femtosecond energy may be less than theplasma generation threshold photodisruption threshold for the specificocular tissue or fluid, or less than the energy threshold for bubbleformation in the specific ocular tissue or fluid, or at a fraction ofthe energy threshold for bubble formation in the specific ocular tissueor fluid.

System 1200 also includes a sensor 1220 oriented along the path so as tosense a first signal associated with a first focus location 1214 withinthe eye 1210 and a second signal associated with a second focus location1216 within the eye 1210. System 1200 further includes a computingdevice 1230 communicatively coupled with the sensor 1220. The computingdevice determines a location of an interface between the fluid and atissue of the eye 1210 in response to the first signal and the secondsignal. System 1200 may also include an additional computing device 1240communicatively coupled with the femtosecond laser 1202 and/or opticalsystem 1204. Computing device 1240 may control laser 1202 and/or opticalsystem 1204 by transmitting signals to those devices. Computing device1240 may also receive feedback from laser 1202 and/or optical system1204. In some embodiments, computing device 1230 and computing device1240 comprise the same device.

Applanation Lens

An applanation lens may be used with the optical system to stabilize theeye during a diagnostic or therapeutic procedure and/or to correct forone or more aberrations, such as astigmatism. FIG. 8 illustratesexemplary applanation lenses that may be used with embodiments of theinvention. Applanation lenses may be placed on the exterior surface ofthe cornea during a diagnostic or therapeutic procedure. In oneembodiment, the applanation lens may be a flat lens 802, with planar topand bottom surfaces. In another embodiment, the applanation lens mayinclude a planar top surface and a curved bottom surface 804. In yetanother embodiment, the applanation lens may include curved top andbottom surfaces 806. The curvature of one or more of the surfaces maycomprise a radius R, which in one embodiment may be between 120 and 130mm, and more commonly about 124 mm.

Applanation lens 806 may be used to correct an aberration, such asastigmatism. Astigmatism may not be noticed on axis, but may be noticedin field. The curvature of applanation lens 806 may balance theastigmatism. Such aberration correction may be important when cuttingrings or arcuate incisions with the optical system. After theapplanation lens is placed atop the cornea, the diagnostic scanprocedures described herein may be used to measure beam spotsize/dimensions so as to provide an indication of any wrinkling that mayoccur due to applanation of the cornea. A similar procedure may beperformed after an intraocular lens (IOL) is placed in the capsular bagto determine if the new lens is wrinkled. The scanning procedure mayalso be performed to detect one or more of the following conditions:curvature of the patient interface contact surface after the applanationlens is applied (e.g., the cornea curvature may be determined after theapplanation lens is applied); bubbles that might be present at themeniscus formed by the contact surface of the patient interface and thecornea; apex and/or vertex location of the contact surface of thepatient interface.

In other embodiments, the applanation lens may be positioned in fluidcommunication with the cornea, such as to reduce intraocular pressurethat may be result from applanation. For example, U.S. patentapplication Ser. No. 13/230,590, the disclosure of which is incorporatedherein by reference, describes the use of an applanation lens that ispositioned proximal to but not contacting the corneal surface. A liquidmay be disposed between the applanation lens and the cornea.Alternatively, instead of using an applanation lens, one or morecomponents of the optical system could adjust to compensate for theastigmatism. This may be specific to systems being looked at forcapsulorhexis, but not specific to a particular laser system.

In some embodiments, the scanning/measurement process is performed witha conjugate system. The indication of a surface is performed with atherapeutic femtosecond laser beam, although in other embodiments, aseparate detection sensing beam may be used. The therapeutic femtosecondlaser beam may be operated at lower non-therapeutic energy levels.

The diagnostic scan procedures and/or therapeutic procedures describedherein may be combined with other diagnostic techniques such as opticalcoherence tomography (OCT) to determine a patient's ophthalmic anatomyprior to a therapeutic treatment. Similarly, the diagnostic scanprocedures described here may be used for pachymetry prior to LASIK orother procedures.

Exemplary Therapeutic and/or Diagnostic Procedures

FIG. 9 illustrates a method 900 for providing capsulorhexis treatment.At block 910, a back surface of the cornea is detected via a diagnosticscan using a femtosecond laser of the optical system. A small gap may beprovided for a safety zone. At block 920, a front surface or interfaceof the lens is detected via the diagnostic scan. At block 930, atherapeutic ablation is delivered through the range between the corneaand the lens via a therapeutic scan. Alternatively or additionally, thefront and back surface of the capsule may be detected during thediagnostic scan and the therapeutic ablation may be delivered betweenthis range or a portion thereof. As described herein, the diagnostic andtherapeutic scans may be delivered via the femtosecond laser of theoptical system. In delivering the scans, the femtosecond laser may beadjusted between a diagnostic/scanning energy level and a therapeuticenergy level.

Another method may involve detecting the cornea and calculating a safescanning/therapeutic distance by determining an absence of signal as thedepth of the laser beam focal position is adjusted away from the cornea.In other words, a safe distance to begin therapeutic treatment mayinvolve determining that a therapeutic starting point is sufficientlyfar from the cornea. The method may also involve scanning through arange of a couple of millimeters or more to determine a minimum andmaximum height of the lens. If nothing else is detected in that range,then therapeutic treatment may proceed.

FIG. 10 illustrates a method for detecting and/or providing therapeutictreatment to an anatomical feature (e.g., capsule, lens, and the like)with an optical system and/or femtosecond laser. At block 1010, astarting scanning depth may be determined. The starting scanning depthmay be about 3 mm from the cornea. At block 1020, a scanning depth isdetermined. The scanning depth represents the depth the focal positionof the laser beam will traverse. In one embodiment, the scanning depthis between 0-6 mm, between 3-6 mm, and the like, although other depthsare possible. The scanning depth is typically a depth where the locationof the capsule, lens, and the like is expected.

At block 1030, a signal spot or light intensity on a camera capturingreflected light is observed to determine a light intensity increase ofthe signal spot. The light intensity increase represents when the focalpoint of the laser beam encounters the capsule. If the lens is tiltedwith respect to the optical axis of the objective or is de-centered, thesignal spot may appear or disappear depending on the position of thelaser beam's focal point. If the laser beam's focal point is in aqueousareas the signal spot intensity may be low. Similarly, when the laserbeam's focal point encounters the lens or is positioned thereon, thesignal spot intensity may be high. At block 1040, the anatomical featuremay be mapped by scanning the laser beam's focal point and observing thesignal spot to determine if the focal point is positioned on or near theanatomical feature (e.g., lens) or on another anatomical feature (e.g.,capsule, aqueous area, and the like).

At block 1050, a therapeutic treatment may be provided by calculating avertical (or horizontal) sidecut and inputting the vertical sidecut intoa control system. In one embodiment, the vertical sidecut may be roughly5-6 mm in diameter. At block 1060, the laser beam intensity may beincreased (e.g., to a therapeutic level) and the laser beam's focalpoint may be scanned in accordance with the vertical sidecut.

The vertical step size of scanning/therapeutic procedure can bevariable. For example, the step size may initially be 10 μm. When ananatomical feature surface is encountered, the step size may be adjustedto 2 μm. The scanning and/or therapeutic step may continue with the 2 μmstep size until the anatomical feature is mapped and/or treated.

In some embodiments, the diagnostic scan may be combined with thetherapeutic treatment. For example, when an anatomical feature (e.g.,capsule) to be treated is encountered, the laser beam intensity may beadjusted to a therapeutic level. The laser beam focus may be adjustedvertically and/or horizontally to provide the desired therapy and thesignal spot may be monitored to determine when the laser beam focusencounters an edge of the anatomical feature and/or when an additionalanatomical feature is encountered.

FIG. 11 illustrates a method for analyzing the ophthalmic anatomy of apatient posterior to the cornea and/or for providing therapeutictreatment to the ophthalmic anatomy. At block 1110, a focus of afemtosecond laser beam is scanned along a path within the patient's eye.A portion of the path may be disposed posterior to the patient's corneaand the path may include a first location and a second location. Atblock 1120, a first reflectance image is acquired. The first reflectanceimage may be associated with the focus disposed at the first location.At block 1130, a second reflectance image is acquired. The secondreflectance image may be associated with the focus disposed at thesecond location. At block 1140, the presence or absence of an ophthalmicanatomical feature of the eye may be determined based on a comparisonbetween the first reflectance image and the second reflectance image. Atblock 1150, the femtosecond laser beam may be operated to providetherapeutic treatment to one or more areas of the anatomical features.The anatomical feature may include a capsular bag and/or a lens withinthe capsular bag. The therapeutic treatment provided by the laser (e.g.,the femtosecond laser) may include disrupting a capsule or lens and mayinclude lens fragmentation, capsulorhexis, and/or capsulotomy. Thefemtosecond laser may be operated at a lower energy level during thescanning process and may be operated at a higher energy level to providethe therapeutic treatment. Although the embodiment of FIG. 11, and otherembodiments described herein, refers to first and second locations, itshould be realized that the diagnostic and/or therapeutic scans mayinclude multiple other locations (e.g., 3^(rd), 4^(th), 5^(th), . . . ,n^(th), etc.) depending on the scan pattern, scan parameters, anatomicalfeature, diagnostic and/or therapeutic procedure, and the like. Forexample, a diagnostic scan may involve 2D or 3D mapping of one or moresurfaces of an anatomical feature, which may involve multiple thousandscan locations at various locations within two dimensional or threedimensional spaces. Likewise, a therapeutic scan may involve multiplethousand scan locations corresponding to various anatomical features ofthe eye.

EXAMPLES

Using the range finding and/or therapeutic treatments described herein,a continuous curvilinear capsulorhexis (CCC) was performed using amodified, extended focal range femtosecond laser, such as the iFS lasermanufactured by Abbott Medical Optics Inc., to locate the surface of thecapsule bag and to perform capsulotomy in cadaver eyes ex-vivo and inrabbits in-vivo. Results demonstrated improved effectiveness of thefemtosecond laser in exact placement, precise sizing, and positioning ofthe anterior capsulotomy.

The cadaver procedure involved using 27 human cadaver globes (corneasintact or removed) to evaluate the femtosecond laser-assisted CCCtreatments. The cadaver globes were measured using a PalmScan handheldpachymeter (Micro Medical Devices) to determine corneal thickness andanterior chamber depth prior to femtosecond laser scanning andtreatment. The eyes were inspected under a surgical microscope for easeof capsular tissue removal, circularity of the capsulotomy, and capsularbag integrity.

Pre-capsulotomy measurement of the anterior chamber depth (ACD) wasperformed with a modified femtosecond laser-guided range-finding featurewith a standard deviation of approximately 0.87 μm. Table 1 belowprovides some data of this process.

TABLE 1 Results of cadaver tissue for comparative analysis of biometryvs. range finding with average percent error converted to microns (0.075μm) Palm Range % Error scan finding normalized 2.54 3.30 19.82 2.52 2.36−26.00 3.68 4.08 −5.02 3.81 4.50 1.66 3.81 4.43 3.04 4.64 4.52 −0.99 Ave% error converted 0.075 μm to microns

The globes tested without corneas had 100% separation at 0.6 μJ energy,similar to recent clinical studies. As shown in Table 2 below, thecapsulotomy tissue removed ranged from 2.5-6 mm in diameter with greaterthan 75% complete separation on all eyes. Calibrated laser settings wereused. All tissue removed was round and had smooth edges.

TABLE 2 Results of cadaver tissue size and associated completeness ofseparation % Complete Diameter separation 6.0 mm  75% 5.0 mm 90-100% 4.5mm  95% 3.5 mm 100% 3.0 mm 80-100% 2.5 mm 100%

A representative image of the precise placement, centration, and uniformcircularity of the femtosecond laser-assisted capsulotomy relative tothe pupil in a cadaver eye immediately following treatment is providedin FIG. 13.

An in vivo rabbit procedure was performed using 18 New Zealand Whiterabbits (average weight approximately 3.27 kg) that underwentfemtosecond laser-assisted CCC treatment in the right eye and manualcapsulorhexis in the left eye. The corneal pachymetry (thickness) andanterior chamber depth of the rabbit eyes were measured pre-operativelyusing a Pentacam HR Scheimpflug camera (Oculus) as shown in FIG. 14A.Immediately following the femtosecond laser scanning and treatmentprocedure the ease of capsular tissue removal, circularity of thecapsulotomy, and capsular bag integrity were assessed. Postoperativeocular healing response, including stability of the capsular bag afterIOL implantation, was monitored from 1-3 months by slit-lampbiomicroscopy (see FIG. 14C).

A preoperative comparison of biometry versus the range finding depthmeasurements was performed. The range-finding process scans yieldedprecise depth positions using the laser at ultra-low energy, such asthose described herein. Machine vision captured the reflected beam'ssharpest images to determine the position and tilt of the anteriorcapsule surface, similar to the range finding processes describedherein. A representative image of the range-finding scan through thecorneal surface, lens surface, and internal structure of the lens isprovided in FIG. 14B.

The biometry data for pachymetry was correlated with the range-findingdata to predict the depth for laser treatment patterns. As shown inTable 3 below, the normalized average error between the two data setswas about −0.52%.

TABLE 3 Results of in vivo rabbit biometry vs. range finding normalizeddata Pentacam Range finding Difference Difference AC depth (mm) PC vs.RF normalized Normalized % Error pach Min Max min (mm) (mm) errornormalized 2.907 3.83 3.94 −0.923 3.171 0.264 0.08 2.863 3.58 3.70−0.717 2.921 0.058 0.02 2.900 3.52 3.64 −0.620 2.861 −0.039 −0.01 2.9443.65 3.80 −0.706 2.991 0.047 0.02 2.956 3.68 3.79 −0.724 3.021 0.0650.02 2.896 3.16 3.32 −0.264 2.501 −0.395 −0.16 SD min RF 0.226 Ave ofdiff Ave % error −0.659 −0.52%

Post treatment capsular size data for 6 rabbit eyes was obtained after 1day and 1 week. The capsulotomy size change over the 1 weekpost-operative time frame was measured via Adobe® Pixel count and showedthat the standard deviation of average change in capsulotomy size was 42μm or less. Right eyes (OD) had laser capsulotomy treatments while Lefteyes (OS) had manual capsulorhexii. Data results are provided in Table 4below.

TABLE 4 Results of in vivo rabbit capsular opening slit lamp imagecapture and measurement at 1 day and 1 week. OD OS Size, day one Size,week one Size, day one Size, week one Vert Horiz Vert Horiz Vert HorizVert Horiz 5.19 5.62 5.01 5.38 3.95 5.16 3.94 4.7  5.36 5.63 5.25 5.5 3.72 4.29 3.43 4.1  5.13 5.71 4.18 4.45 3.99 4.80 3.86 4.43 5.03 5.525.07 5.33 4.16 4.28 4.1  4.41 4.91 5.64 5.16 5.48 4.37 4.59 4.4  5.044.77 5.36 4.96 5.54 3.63 4.17 3.26 3.87 Average 5.07 5.58 4.94 5.28 3.974.55 3.83 4.43 SD 0.21 0.12 0.39 0.41 0.27 0.39 0.42 0.42

A representative image of a treated rabbit eye showing the accuracy ofthe femtosecond laser-assisted capsulotomy placement, centration, anduniform circularity over the intraocular lens implant at 1 monthpost-operative is provided in FIG. 14C.

The above described study shows that the femtosecond lasers describedherein are capable of precisely controlled capsulotomy. The femtosecondlaser-assisted capsulotomy depth accuracy is repeatable and precise asdemonstrated by the comparative analysis of biometry data with averagenormalized percent accuracy error of −0.52 percent. The in vivo studiesdemonstrated that the SD of average change in capsulotomy size over oneweek was 42 μm or less. The ex-vivo and in-vivo studies alsodemonstrated excellent surgical performance of the femtosecondlaser-assisted capsulotomy with respect to lens capsule integrity andstability following capsulotomy and IOL implantation. Accordingly, thefemtosecond lasers and/or treatment methods described herein and used inthe above described study offer improved treatment capability, accuracy,and precision over manual cataract surgery techniques.

Exemplary Field Upgrade Unit

As mentioned previously, the therapeutic and/or diagnostic scanningprocedures described herein may be provided in a field upgrade unit thatmay be removably coupled with pre-existing laser optical systems. In anon-limiting embodiment, a field upgrade unit was fitted with a cornealfemtosecond laser workstations to adapt the workstation to perform lasercapsulotomy. The field upgrade unit, and several experimental proceduresinvolving the field upgrade unit, is described below. The field upgradeunit allowed the pre-existing laser optical system to perform thefollowing functions: locate the anterior lens capsule, extend the focusrange of the pre-existing laser optical system to reach the capsule,ensure that the energy density at the focus is above the cut threshold,ensure that laser irradiance at the retina is below ANSI limits, ensurethat the existing corneal functions remain intact, and the like.

To adapt the pre-existing laser optical system to the therapeutic and/ordiagnostic scanning procedures described herein (e.g., laser capsulotomyand the like), the pre-existing laser optical system was implementedwith the described range finder and zoom beam expander (ZBX). In oneembodiment, several corneal workstations were upgraded as well and/orthe laser optical system's existing patient interface (PI) was utilizedin a unique way to form a liquid interface. The feasibility of theadapted optical systems was then analyzed via computational modeling,measurements, tests with ex-vivo and in-vivo eyes, and human clinicalstudy. An embodiment of an adapted optical system is shown in FIG. 15.As shown in FIG. 15, modifications to pre-existing optical systems thatmay allow the pre-existing systems to perform the described therapeuticand/or diagnostic scanning procedures (e.g., capsulotomy and the like)may include implementing the described range finder, Zoom Beam Expander(ZBX), and/or the liquid Patient Interface (PI). These components areall shown in FIG. 15 by dashed lines.

The range finder implemented with the pre-existing optical system wasdesigned to image the focus of the surgical beam based on thereflectivity of the third Purkinje image PIII, which is approximately0.016%. During range finding, the pulse energy was set below the opticalbreakdown (OB) threshold energy as determined by the onset of bubbleformation in water. The capsule depth was determined by imaging thelaser focus onto a CCD camera as the laser focus was scanned through thecapsule. The accuracy, which depends on the Rayleigh range of the focus,was verified to be within ±20 μm. Because the laser beam of the abovedescribed adapted optical system is used for both measurement andsurgical purposes, this design substantially reduces or eliminates therisk of registration error between the surgical laser and a separatemeasurement.

The Zoom Beam Expander (ZBX) implemented in the pre-existing opticalsystem was designed to replace the original fixed beam expander. The ZBXmay use the same set of lenses as the original fixed beam expander, thusensuring the same or similar optical prescription when the system is runin the corneal workstation mode. The focal depth range with the ZBX maybe extended from a range of 0 mm to 1.2 mm (the approximate range oforiginal fixed beam expander) to about 0 mm to about 7.0 mm. This rangemeets the laser capsulotomy needs for approximately 99% of cataractouseyes, which typically have anterior chamber depths in the range of about2.0 mm to about 4.0 mm.

In experimental studies involving no cornea, the energy sufficient forcapsule cutting was measured at about 3 to 4 times the OB thresholdenergy at the corresponding depth in water. With this design, the highnumerical aperture (NA) of the pre-existing optical system may bepreserved, which may ensure low threshold energy (˜1/NA2) forcapsulotomy, high sensitivity (˜1/NA2) for range finding, and/or lowpeak irradiance at retina (˜1/NA4). A simulated 4-year cycling of keycomponents was performed to assess the reliability of the adaptedoptical systems for both corneal and capsulotomy functions. The measuredresult was a change of less than 2 μm variation in focal depth with notrend. At the system level, a simulation of 1-year ZBX cycling wasperformed to determine system performance at flap creation conditions.

As briefly described herein, the patient interface (PI) can affect thefocal quality by deforming the cornea and introducing wrinkles on theposterior surface. A liquid PI can minimize this effect. The focalquality of a beam passing through a liquid PI with no cornea and with acadaver cornea is shown in FIG. 16. As shown, the cornea may introducechanges to the focus, but the basic beam profile may be well maintained.

A comparison of the effects of laser cutting in the lens of ex-vivo pigeyes docked with a liquid PI (LI) and flat applanating PI (FA) are shownin FIG. 17. At 1.6 μJ, the liquid PI (LI) may yield stronger tissueeffects than the flat applanating PI (FA). At 1.8 μJ, the liquid PI (LI)and the flat applanating PI (FA) may both produce strong tissue effectsat the full circumference. Since the liquid PI (LI) typically requireslower cut energy, it was selected for the clinical study.

In regards to retina safety, ANSI, ICE, and ICNIRP require the same orsimilar Maximum Permissible Exposures (MPE) in the retinal hazard regionfor lasers. The most restrictive one of the three MPEs (i.e., MPE forsingle pulse, MPE for average power, and MPE for grouped pulse) must bemet. These MPEs are determined by wavelength, pulse duration, NA of thebeam, pulse repetition frequency, and the exposure time. The irradianceat the retina produced by the laser depends on pulse energy, pulserepetition frequency, NA of the beam, the focus location, and thestructure of eye. The studies conducted demonstrated that the peakirradiance of the modified optical system at the retina is well belowthe most restrictive ANSI MPE for grouped pulse.

The above described field upgrade unit and studies demonstrate thefeasibility of adapting a pre-existing laser optical system, such as afemtosecond laser corneal workstations, to perform laser capsulotomy. Asdescribed herein adapting a pre-existing laser optical system mayinvolve implementing the described range finder, zoom beam expander(ZBX), and/or a novel use of an existing patient interface (PI) to forma liquid interface. The performance of the modified or upgraded systemsmay include one or more of the following: locating the anterior lenscapsule by the range finder within ±20 μm in depth; extending the laserfocal range to about 0 mm to 7 mm by using ZBX—a range that issufficient to cover the capsulotomy needs for approximately 99% ofcataractous eyes; setting the diameter for laser capsulotomy to anyvalue within about 6.5 mm; ensuring that all three ANSI MPE limits aremet; ensuring that the upgraded systems provide equivalent performancein flap creation mode compared with existing the corneal workstations;and the like.

A femtosecond laser capsulotomy clinical trial was conducted using theabove described systems and methods for 19 cataract patients. The humanclinical trials validated the laser cut time at between about 12˜40seconds. The upgrades described herein may be implemented via fieldservice at moderate costs.

While the disclosure has been described in connection with specificembodiments thereof, it will be understood that it is capable of furthermodifications. This application is intended to cover many variations,uses, or adaptations of the disclosure following, in general, thedisclosed principles and including such departures from the disclosureas come within known or customary practice within the art to which thedisclosure pertains and as may be applied to the essential featureshereinbefore set forth.

What is claimed is:
 1. A system for analyzing a patient's eyecomprising: a laser configured for directing a pulsed laser beam along apath; an optical beam-splitting device disposed along the path from thelaser, the optical beam-splitting device configured to polarize androtate the polarity of the laser beam; an objective component includinga focusing lens to focus the laser beam within the eye; a sensororiented along the path, wherein the sensor receives a back-reflectedlaser beam from the eye, and generates a signal corresponding to thatlaser beam; and a computing device communicatively coupled with thesensor and configured to receive the signal, wherein the computingdevice determines a position of an anatomical feature of the eye basedon the signal.
 2. The system of claim 1, wherein the optical beamsplitting device comprises: a polarization beam splitter configured totransmit a laser beam oriented in a first linear direction; and aquarter-wave plate configured to rotate in a first circular directionthe laser beam transmitted through the polarization beam splitter towardthe eye, and to transform the rotation of the back-reflected laser beamfrom a second circular direction to a second linear direction.
 3. Thesystem of claim 1, wherein the optical beam-splitting device comprises apartially reflecting and a partially transmitting mirror.
 4. The systemof claim 1, wherein the optical beam-splitting device comprises aFaraday rotator subsystem configured to polarize and rotate the laserbeam along the path from the laser.
 5. The system of claim 4, whereinthe Faraday rotator subsystem comprises a polarization beam-splitter anda Faraday rotator.
 6. The system of claim 4, wherein Faraday rotatorsubsystem comprises a Faraday optical isolator.
 7. The system of claim1, wherein the sensor is selected from the group consisting of a CCDcamera, a photodiode detector, and a Shack-Hartmann wavefront sensor. 8.The system of claim 1, wherein the sensor comprises a lens, a pinhole,and a photo detector.
 9. The system of claim 1, wherein the lasercomprises a non-ultraviolet, ultra-short pulsed laser.
 10. A system foranalyzing an eye of a patient comprising: a laser configured fordirecting a pulsed laser beam along a path; a polarization beam-splitterdisposed along the path from the laser and configured to transmit alaser beam oriented in a first linear direction; a quarter-wave platedisposed between the polarization beam splitter and the eye, andconfigured to rotate in a first circular direction the laser beam thatis transmitted by the polarization beam splitter toward the eye, and totransform the rotation of a back-reflected laser beam from a secondcircular direction to a second linear direction; an objective componentincluding a focusing lens to focus the laser beam within the eye; aconfocal system comprising a lens and a pinhole oriented to focus theback reflected laser beam from the eye, wherein the back-reflected laserbeam is transmitted to the confocal system by the polarization beamsplitter; a sensor oriented along the path, wherein the sensor receivesthe back-reflected laser beam from the confocal system and generates asignal corresponding to that laser beam; and a computing devicecommunicatively coupled with the sensor and configured to receive thesignal, wherein the computing device determines a position of ananatomical feature of the eye based on the signal.
 11. The system ofclaim 10, wherein the sensor is selected from the group consisting of aCCD camera, a photodiode detector, and a Shack-Hartmann wavefrontsensor.
 12. The system of claim 10, wherein the laser comprises anon-ultraviolet, ultra-short pulsed laser.
 13. A system for analyzing aneye of a patient comprising: a laser configured for directing a laserbeam along a path; a Faraday rotator subsystem configured to polarizeand rotate the laser beam along the path; an objective componentincluding a focusing lens to focus the laser beam within the eye; aconfocal system comprising a lens and a pinhole oriented to focus a backlaser beam energy from the eye, wherein the back-reflected laser beam istransmitted to the confocal system by the Faraday rotator subsystem; asensor oriented along the path, wherein the sensor receives theback-reflected laser beam from the confocal system and generates asignal corresponding to that laser beam; and a computing devicecommunicatively coupled with the sensor and configured to receive thesignal, wherein the computing device determines a position of ananatomical feature of the eye based on the signal.
 14. The system ofclaim 13, wherein the Faraday rotator subsystem comprises a polarizationbeam splitter and a Faraday rotator.
 15. The system of claim 13, whereinFaraday rotator subsystem comprises a Faraday optical isolator.
 16. Thesystem of claim 13, wherein the sensor is selected from the groupconsisting of a CCD camera, a photodiode detector, and a Shack-Hartmannsensor.
 17. The system of claim 13, wherein the laser comprises anon-ultraviolet, ultra-short pulsed laser.
 18. A system for analyzing aneye of a patient comprising: a first laser configured for directing afirst laser beam along a path; a second laser configured for directing asecond laser beam along the path, the second laser beam having a shorterwavelength than the first laser beam; a beam-splitter configured toreflect the second laser beam along the path toward the eye, and totransmit a back reflected second laser beam from the eye toward asensor; a dichroic mirror configured to reflect the second laser beamalong the path toward the eye and to transmit the first laser beam alongthe path toward the eye; an objective component including a focusinglens to focus the first and second laser beams within the eye; a sensororiented along the path, wherein the sensor receives the back reflectedsecond laser beam and generates a signal corresponding to that laserbeam; and a computing device communicatively coupled with the sensor andconfigured to receive the signal, wherein the computing devicedetermines a position of an anatomical feature of the eye based on thesignal.
 19. The system of claim 18, wherein a portion of the secondlaser beam is transmitted through the beam-splitter and the systemfurther comprises a beam dump that absorbs the portion of the secondlaser beam transmitted through the beam splitter.
 20. The system ofclaim 18, wherein the sensor is selected from the group consisting of aphotodiode detector, a CCD camera, and a Shack-Hartmann wavefrontsensor.
 21. The system of claim 18, wherein the first laser comprises anon-ultraviolet, ultra-short pulsed laser.